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Author

Yoshinori Nagata

Bio: Yoshinori Nagata is an academic researcher. The author has contributed to research in topics: Wave power & Whale. The author has an hindex of 4, co-authored 7 publications receiving 121 citations.
Topics: Wave power, Whale, Wave height, Amplitude, Breakwater

Papers
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01 Jan 2002
TL;DR: The Mighty Whale is a floating wave power device based on the Oscillating Water Column (OWC) principle, which converts wave energy into electric energy, and produces a relatively calm sea area behind.
Abstract: Mighty Whale is a floating wave power device based on the Oscillating Water Column (OWC) principle. It converts wave energy into electric energy, and produces a relatively calm sea area behind. The open sea tests were begun in September 1998 in Gokasho Bay, Nansei Town, Mie Prefecture. Measurements collected since then include performance data in typhoon seasons. This paper presents the measurements of wave energy absorption, floating body motion, and wave height dissipation. It is expected that these results will be useful in the design of offshore wave power devices in the future.

78 citations

Proceedings ArticleDOI
01 Jan 2002
TL;DR: In this paper, the characteristics of wave conditions, wave energy absorption, response of hull-motion and wave height dissipation based on the results of the open sea tests are presented.
Abstract: This paper presents the characteristics of wave conditions, wave energy absorption, response of hull-motion and wave height dissipation based on the results of the open sea tests. 0.5–1.0m of significant wave height and 6–7 seconds of significant wave period appear the most predominant, and average wave energy is estimated 4.88kW/m around the test site. Average power output for the test is approximately 6kWh and the maximum total energy efficiency is around 15% that is ranging from 6–7 seconds of significant wave period. Slow drift oscillation of hull was observed motion in surge, sway and yaw and the value of its amplitude almost equal to estimated values in design stage. Then the mean value of transmission coefficient is about 0.8 under 8.0 seconds of significant wave period. We are considering that the results of the tests should be useful for optimum design of an offshore floating type wave power device.Copyright © 2002 by ASME

21 citations

Patent
11 Sep 2002
TL;DR: In this paper, the authors proposed a marine self-support equipment for a large-sized floating body structure capable of being stably moored even in a sea area having the deep depth of water and selfsupporting energy such as required power and water.
Abstract: PROBLEM TO BE SOLVED: To provide marine self-support equipment for a large-sized floating body structure capable of being stably moored even in a sea area having the deep depth of water and self-supporting energy such as required power and water. SOLUTION: The large-sized floating structure 10 installed on the sea is installed by being connected with a floating breakwater bank 20 in a breakwater sea area of the floating breakwater bank 20 moored and installed at the bottom of the sea and equipment for self-supporting required power is constituted by mounting power generation equipment using natural energy usable in the breakwater bank 20 and the large-sized floating body structure 10. As a result, a mooring rope for installing the large-sized structure 10 becomes unnecessary, the large-sized floating structure 10 can be installed in a breakwater sea area, the structure 10 can be installed in an offing having the deep depth of water, a vessel is capable of approaching and coming alongside the pier, and power is self-supported by mounting the power generation equipment using natural energy usable on the sea on the floating breakwater bank and the large-sized floating structure.

5 citations

Patent
11 Sep 2002
TL;DR: In this article, the problem of providing a mooring structure of a large-sized floating body structure applicable to a deep sea area and enabling the installation of the floating body structures adjacently to a floating breakwater in order to install the floating structure in an effective area of the fixed breakwater is addressed.
Abstract: PROBLEM TO BE SOLVED: To provide a mooring structure of a large-sized floating body structure applicable to a deep sea area and enabling the installation of the floating body structure adjacently to a floating breakwater in order to install the floating body structure in an effective area of the floating breakwater. SOLUTION: The floating breakwater 20 is moored by a captive chain 30 of which the end part is connected to an anchor 40 fixed on the bottom of the sea. The floating structure 10 is constructed by being moored to an intermediate sinker 31A interposed between inner side captive chains 31 thereof through a connecting chain 50.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the development of wave energy utilization since the 1970s is discussed, with a focus on the characterization of the wave energy resource; theoretical background, with especial relevance to hydrodynamics of wave absorption and control; how a large range of devices kept being proposed and studied, and how such devices can be organized into classes; the conception, design, model-testing, construction and deployment into real sea of prototypes.
Abstract: Sea wave energy is being increasingly regarded in many countries as a major and promising resource. The paper deals with the development of wave energy utilization since the 1970s. Several topics are addressed: the characterization of the wave energy resource; theoretical background, with especial relevance to hydrodynamics of wave energy absorption and control; how a large range of devices kept being proposed and studied, and how such devices can be organized into classes; the conception, design, model-testing, construction and deployment into real sea of prototypes; and the development of specific equipment (air and water turbines, high-pressure hydraulics, linear electrical generators) and mooring systems.

2,115 citations

Journal ArticleDOI
TL;DR: A comprehensive review of wave energy converters and air turbines can be found in this paper, together with a survey of theoretical, numerical and experimental modelling techniques of OWC converters.

594 citations

Journal ArticleDOI
TL;DR: In this paper, the authors bring the latest status on integration of wave energy device with other marine facilities, which is the breakwater structure that may possibly aid to cost sharing, and show that the integration opens up a new dimension to acknowledge the technology harnessing ocean wave, especially for the Asian countries experiencing medium wave condition.
Abstract: One of the most abundant energy sources exists in this world is the ocean wave energy. By far, it has shown to be the most clean, renewable, predicted energy and has raised the potential to compete with the current use of non-renewable energy sources. Recent research conducted on wave energy invention has opened a new dimension to slowly reduce the dependency on fossil fuel by introducing new technology on the renewable world but relatively lacking in economical aspect. This review brings the latest status on integration of wave energy device with other marine facilities, which is the breakwater structure that may possibly aid to cost sharing. Most researches done on this field highlighted countries experiencing rough sea condition and focused less on countries with medium wave condition as faced by the Asian continent. The potential for energy extraction and wave dissipation for medium wave condition will be discussed in this review by considering several aspects including reliability, effectiveness and performance. Finally, this review shows that the integration opens up a new dimension to acknowledge the technology harnessing ocean wave, especially for the Asian countries experiencing medium wave condition.

267 citations

Journal ArticleDOI
TL;DR: In this article, a review of the state of the art on self rectifying air turbines, which could be used for wave energy conversion, has been presented, and the overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of their starting and running characteristics.

221 citations

Journal ArticleDOI
14 May 2018-Energies
TL;DR: In this paper, the background of wave energy harvesting technology, its evolution, and the present status of the industry is reviewed, and solutions are suggested while discussing the challenges in order to increase awareness and investment in wave energy industry as a whole.
Abstract: Wave energy is substantial as a resource, and its potential to significantly contribute to the existing energy mix has been identified. However, the commercial utilization of wave energy is still very low. This paper reviewed the background of wave energy harvesting technology, its evolution, and the present status of the industry. By covering the theoretical formulations, wave resource characterization methods, hydrodynamics of wave interaction with the wave energy converter, and the power take-off and electrical systems, different challenges were identified and discussed. Solutions were suggested while discussing the challenges in order to increase awareness and investment in wave energy industry as a whole.

175 citations